James Madison first suggested the need for a federal district in the Federalist No. 43. He argued that the national capital needed to be distinct from the states, in order to provide for its own maintenance and safety. An attack on the Congress at Philadelphia in June 1783 by a mob of angry soldiers emphasized the need for the government to see to its own security. In what later became known as the Compromise of 1790, Madison, Alexander Hamilton, and Thomas Jefferson came to an agreement that the federal government would assume war debt carried by the states, on the condition that the new national capital would be located in the South. On July 16, 1790, the Residence Act provided for a new permanent capital to be located on the Potomac River. George Washington chose the exact site for the city, and it was named in his honour on September 9, 1791. The initial shape of the federal district was a diamond, measuring 10 miles (16 km) on each side, totaling 100 square miles (260 km²). As originally platted, both Maryland and Virginia ceded portions of their territory to form the new capital. During 1791-92, Andrew Ellicott and Benjamin Banneker surveyed the border of the District with both states, placing boundary stones at every mile point; many of these are still standing. The federal district was named the District of Columbia; Columbia being a poetic name for the United States in use at that time. On December 1, 1800, the offices of the Federal government were officially transferred to the District. The Organic Act of 1801 officially incorporated the District of Columbia and placed it under the exclusive control of Congress. The District was organised into two counties: the County of Washington on the north bank of the Potomac, and the County of Alexandria on the south bank. The laws of both Maryland and Virginia continued to apply in each county; however, following this Act, citizens in the District were no longer residents of either state, thus ending their representation in Congress. The plans for the City of Washington were largely the work of Pierre Charles L’Enfant, a French-born architect, engineer, and city planner who first arrived in the American colonies as a military engineer with Major General Lafayette. Although plans for the new City of Washington placed it in the geographic centre of the federal territory, other communities such as Georgetown were also located in the District of Columbia . On August 24, 1814, British forces burned the capital during the most notable raid of the War of 1812, in retaliation for the sacking and burning of York (modern-day Toronto). Initially, the British had approached the city hoping to secure a truce, but were fired upon, which ultimately led to the sacking of government buildings. The Capitol, Treasury, and White House were burned and gutted. Most government buildings were quickly repaired, but the Capitol, which was at the time largely under construction, would not be completed until 1868. In the 1830s the District's southern county of Alexandria went into economic decline, due in part to heavy competition from the port of Georgetown, which was further inland and on the C&O; Canal. At the time, Alexandria was a major market in the American slave trade, but rumors circulated that abolitionists were attempting to end slavery in the nation's capital. In 1846, partly to avoid an end to the lucrative slave trade, a referendum to ask for the retrocession of Alexandria back to the Commonwealth of Virginia succeeded. Congress complied on July 9 of that year. Four years later, the Compromise of 1850 outlawed the slave trade in the District, though not slavery itself. Washington remained a small city until the outbreak of the American Civil War in 1861. The significant expansion of the federal government as a result of the war led to notable growth in the city's population, as did a large influx of freed slaves. By 1870, the District's population had grown to nearly 132,000. Despite the city's growth, Washington still had dirt roads and lacked basic sanitation; the situation was so bad that some members of Congress proposed moving the capital elsewhere.